Counties where theIowa Pleistocene land snail can be found are in black.
Iowa
Pleistocene Land Snail Discus macclintocki
Status: Endangered
Description: The Iowa Pleistocene
land snail is about one-fourth inch in diameter as an adult. The
shell is tightly coiled and almost dome-shaped. Shell color is brown
or greenish-white.
Habitat and Habits: This species is limited to cold air talus
slopes. Air circulation and water infiltration into fractured rock
formations produce underground ice which slowly melts during summer,
producing a constant flow of cold moist air which filters through
the rock talus. These slopes provide a habitat that is unique
because temperature changes are much less than adjacent areas both
during summer and winter. The Iowa Pleistocene land snail may
produce multiple broods with the average number of eggs being three.
The eggs are laid under fallen logs, in moist rock crevices and in
the soil. Because of the patchy distribution of cold air slopes,
there is little possibility for natural colonization or
recolonization of slopes presently devoid of snails.
Distribution: The Iowa Pleistocene land snail is currently
known only in Illinois and Iowa, with all but one of the known
populations occurring in Iowa. There are about 30 known sites for
this species in Iowa.
Conservation Efforts: The U.S. Fish & Wildlife Service, the
Iowa Department of Natural Resources, and The Nature Conservancy are
working with landowners and are acquiring the most important slopes
to ensure the long-term survival of this species.
Reasons For Listing: Human-caused disturbances such as overgrazing,
logging, road construction and quarrying have all reduced the
habitat available for the Iowa Pleistocene land sail.
Funding Provided
by U.S. Environmental Protection Agency and
